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BUG: na parameter for str.startswith and str.endswith not propagating for Series with categorical dtype #36249

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Merged
merged 10 commits into from
Sep 12, 2020
2 changes: 1 addition & 1 deletion doc/source/whatsnew/v1.1.3.rst
Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,7 @@ Fixed regressions

Bug fixes
~~~~~~~~~
-
- Bug in :meth:`Series.str.startswith` and :meth:`Series.str.endswith` with ``category`` dtype not propagating ``na`` parameter (:issue:`36241`)

.. ---------------------------------------------------------------------------

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2 changes: 1 addition & 1 deletion pandas/core/strings.py
Original file line number Diff line number Diff line change
Expand Up @@ -2050,7 +2050,7 @@ def wrapper2(self, pat, flags=0, **kwargs):
@forbid_nonstring_types(forbidden_types, name=name)
def wrapper3(self, pat, na=np.nan):
result = f(self._parent, pat, na=na)
return self._wrap_result(result, returns_string=returns_string)
return self._wrap_result(result, returns_string=returns_string, fill_value=na)

wrapper = wrapper3 if na else wrapper2 if flags else wrapper1

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40 changes: 32 additions & 8 deletions pandas/tests/test_strings.py
Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,8 @@ def assert_series_or_index_equal(left, right):
("decode", ("UTF-8",), {}),
("encode", ("UTF-8",), {}),
("endswith", ("a",), {}),
("endswith", ("a",), {"na": True}),
("endswith", ("a",), {"na": False}),
("extract", ("([a-z]*)",), {"expand": False}),
("extract", ("([a-z]*)",), {"expand": True}),
("extractall", ("([a-z]*)",), {}),
Expand Down Expand Up @@ -58,6 +60,8 @@ def assert_series_or_index_equal(left, right):
("split", (" ",), {"expand": False}),
("split", (" ",), {"expand": True}),
("startswith", ("a",), {}),
("startswith", ("a",), {"na": True}),
("startswith", ("a",), {"na": False}),
# translating unicode points of "a" to "d"
("translate", ({97: 100},), {}),
("wrap", (2,), {}),
Expand Down Expand Up @@ -838,15 +842,23 @@ def test_contains_for_object_category(self):
expected = Series([True, False, False, True, False])
tm.assert_series_equal(result, expected)

def test_startswith(self):
values = Series(["om", np.nan, "foo_nom", "nom", "bar_foo", np.nan, "foo"])
@pytest.mark.parametrize("dtype", [None, "category"])
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we want to parameterize over 'string' dtype as well rigth?

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string arrays are already tested here
https://github.com/pandas-dev/pandas/blob/1.1.x/pandas/tests/test_strings.py#L3530-L3531

parametrizing over string dtype and na=True/False was making it a bit tricky as these methods return boolean series causing a dtype mismatch (boolean vs object)

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@pytest.mark.parametrize("null_value", [None, np.nan, pd.NA])
@pytest.mark.parametrize("na", [True, False])
def test_startswith(self, dtype, null_value, na):
# add category dtype parametrizations for GH-36241
values = Series(
["om", null_value, "foo_nom", "nom", "bar_foo", null_value, "foo"],
dtype=dtype,
)

result = values.str.startswith("foo")
exp = Series([False, np.nan, True, False, False, np.nan, True])
tm.assert_series_equal(result, exp)

result = values.str.startswith("foo", na=True)
tm.assert_series_equal(result, exp.fillna(True).astype(bool))
result = values.str.startswith("foo", na=na)
exp = Series([False, na, True, False, False, na, True])
tm.assert_series_equal(result, exp)

# mixed
mixed = np.array(
Expand All @@ -867,15 +879,23 @@ def test_startswith(self):
)
tm.assert_series_equal(rs, xp)

def test_endswith(self):
values = Series(["om", np.nan, "foo_nom", "nom", "bar_foo", np.nan, "foo"])
@pytest.mark.parametrize("dtype", [None, "category"])
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same as above

@pytest.mark.parametrize("null_value", [None, np.nan, pd.NA])
@pytest.mark.parametrize("na", [True, False])
def test_endswith(self, dtype, null_value, na):
# add category dtype parametrizations for GH-36241
values = Series(
["om", null_value, "foo_nom", "nom", "bar_foo", null_value, "foo"],
dtype=dtype,
)

result = values.str.endswith("foo")
exp = Series([False, np.nan, False, False, True, np.nan, True])
tm.assert_series_equal(result, exp)

result = values.str.endswith("foo", na=False)
tm.assert_series_equal(result, exp.fillna(False).astype(bool))
result = values.str.endswith("foo", na=na)
exp = Series([False, na, False, False, True, na, True])
tm.assert_series_equal(result, exp)

# mixed
mixed = np.array(
Expand Down Expand Up @@ -3552,6 +3572,10 @@ def test_string_array(any_string_method):
assert result.dtype == "boolean"
result = result.astype(object)

elif expected.dtype == "bool":
assert result.dtype == "boolean"
result = result.astype("bool")

elif expected.dtype == "float" and expected.isna().any():
assert result.dtype == "Int64"
result = result.astype("float")
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